Riveting System for Composite Aircraft Shells
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Solution Overview
Problem
Current riveting methods for aircraft fuselage sections, particularly those using composite materials, face challenges in achieving high precision due to the heavy architecture of existing equipment and issues with drilling chips and rivet protrusion, which affect the mechanical integrity and turbulence of the shell structures.
Innovation Solution
A riveting system with a multiple head device equipped with a drilling head, adhesive applicator, pressure device, and thickness measuring system, featuring a compensating joint and containment sleeve to ensure precise drilling and riveting, minimizing chip penetration and rivet protrusion, and using a fluidic circuit for detecting thickness and pressure variations to select the appropriate rivet length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If riveting equipment uses numerous sensors to detect thrust and position, then measurement precision is improved, but device complexity increases significantly
Solution Approach 1:
The patent extracts the thrust detection function from a complex multi-sensor system and concentrates it in a single load detector integrated into the pressure device. This single detector measures the thrust applied by the external working head, eliminating the need for multiple sensors and complex measurement systems while maintaining adequate precision for the riveting process
Solution Approach 2:
The pressure device serves multiple functions: it applies compression thrust to the shell structure, houses the load detector for thrust measurement, and provides structural support for the external working head. This multi-functionality reduces the need for separate dedicated components for each function, simplifying the overall equipment architecture
2Productivity
If drilling is performed without adequate containment, then productivity is improved, but chip penetration into gaps occurs causing harmful effects
Solution Approach 1:
The containment sleeve acts as an intermediary element between the drilling operation and the surrounding environment. It captures and contains drilling chips generated during the high-speed drilling process, preventing them from penetrating into gaps between the shell structure and reinforcement ribs, while allowing the drilling operation to proceed at high productivity
3Manufacturing precision
If rivet head protrudes minimally from the panel surface, then manufacturing precision is improved, but the difficulty of detecting and measuring increases
Solution Approach 1:
The load detector provides real-time feedback on the thrust applied during riveting. By monitoring the thrust variation as the rivet head is formed and seated, the system can determine when the rivet head has achieved the desired minimal protrusion level, enabling precise control without requiring direct measurement of the protrusion itself
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves enhanced precision and reduced deformations in riveting composite materials, preventing chip penetration and minimizing rivet protrusion, thereby improving the mechanical integrity and reducing operational errors in aircraft fuselage manufacturing.
Implementation Method 1
a fluidic circuit in fluid connection with the inner duct internal to the detection rod; a pressure variation detector arranged to detect pressure variations occurring in the fluidic circuit and/or in the inner duct internal to the detection rod, whenever the detection rod is inserted in or removed from an aperture in a wall
Implementation Method 2
one of the substantially tubular segments has a sucking aperture arranged to cause external air to flow into the containment sleeve and arranged to be closed and/or covered by another one of the substantially tubular segments due to a contraction of the containment sleeve, so as to reduce the air flow passing through the sucking aperture itself
Data Source
AI summary
In order to rivet a light alloy added reinforcement rib (13) on a shell structure made of composite material (11), an external working head (21) is brought near to the external side of the wall of the shell structure (11), until a predetermined thrust is applied; an internal working head (45) is brought near to the internal side of the wall of the shell structure (11), until the load detector of the external (21) detects a predetermined variation of the thrust applied to the shell structure by the external working head (21); with the external working head (21) a thrust is applied to the external side of the shell structure (11), equal to a predetermined compression force, necessary for drilling. This allows the shell structure (11) be drilled with a cheaper apparatus, since only one of the two drilling robots (38, 45) used is provided with pressure sensors.